Tractor shoes



3 Sept. 8, 1959 w. w.. WELLER TRACTOR SHOES 2 Sheets-Sheet 1 Filed July 17, 1958 Fig- Inveni-or B5, Mae! and QMMM W. W. WELLER Sept. 8, 1959 TRACTOR SHOES 2 Sheets-Sheet 2 Filed July 17, 1958 w r n mm 8 2 s mv United rates This invention relates to so-called tractor shoes of the kindto be mounted on the endless track of a track-laying vehicle. j

The conventional mode of achieving effective traction in a track-laying vehicle is by way of individual shoes that are arranged in an articulated assembly about the track, and the shoes are removably related to the track to enable individual repair and replacement to be accomplished. It is common practice to form each such shoe with a so-called sole plate and a grouser which is merely a bar-type projection on the ground-engaging side of the sole plate, and this grouser is what digs into the ground during the course of movement of the track of the vehicle.

In the course of engaging the ground, the plate of the shoe is subjected to a great deal of stress so far as upward bending at the side is concerned, particularly on uneven ground. Conventionally, the shoe is joined to the track by bolts occupying openings in the sole plate, and .there is a great deal of stressing of the walls in the plates of the shoes where the bolts are located, especially in those instances where the portion of the shoe having the bolt openings is composed of manganese steel.

The primary objects of the present invention are to increase the traction efiiciencies of shoes of the foregoing kind, to build into the shoe a great deal of resistance to bending, and to prevent to a large degree distortion of the aforementioned bolt openings. Specifically, it is the object of the present invention to construct a shoe of the foregoing kind with a grouser having a sloped leading or forward face, having end sections on the sole plate that are disposed in inclined planes, having bolt openings that are work hardened and having all corners rounded. Resultantly, there is easy entry of the grouser into and out of the ground with practically no hang-up due to right-angled corners, the sole plate is inherently resistive to vertical bending, and the bolt holes are inherently resistive to stretching or distorting.

' Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what isnow considered to be the best mode contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired .by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

Fig. 1 is a top plan view of a track shoe constructed inaccordance with-the present invention;

Fig. 2 is an end view taken on the line 2'2 of Fig. 1;

Fig. 3 is a front elevation taken on the line 33 of Fig. 1;

Figs. land 5 are sections taken respectively on the 'l-4 and.5--5 of Fig. 1;

atom:

' Fig. 6 is a schematic view illustrating the action of the present shoe;

Fig. 7 is a sectional view taken on the line 77 of Fig.-

6; and

Fig. 8 is a series of sectional views showing work hardening of bolt holes.

The present invention is illustrated in Figs. 1 to 3' inclusive as embodied in a shoe 10 of the kind to be removably connected to the endless track T, Fig. 6, of an overland track-laying vehicle such as a bulldozer, tractor or the like, and reference will be hereinafter made to Figs. 6 and 7 explaining some of the advantageous results of the present invention.

The shoe 10 represents a one-piece casting of manganese steel or the like and includes a so-called sole or tread plate 12 which is the portion of the shoe which will lie normally in a horizontal plane when the shoe is mounted on the track T. Except for certain projections to be described, the sole plate is of substantially uniform cross-section thickness. While the shoe of the present invention is conveniently a cast part, the same can beforged if desired, or fabricated by various techniques.

As will be observed in Fig. 1, the plate 12 is generally rectangular in plan view, and the left and right side and rear (trailing edge) limits thereof are defined by a continuous raised bead or bulb edge rib 15 of rounded crossscction throughout which greatly strengthens and reinforces the plate 12. This rib is located on what constitutes the ground engaging face of the shoe, and the provision of such a raised edge on the plate 12 effectively stiffens the latter and establishes a great deal of resistance to-bending or twisting of the plate 12 during the course of field operation. By rounding the rib 15, as well as allcorners of the shoe as will be noted, the shoe is prevented from hanging up on uneven ground, rock beds, and so on.

Projecting vertically from what constitutes the ground engaging face of plate 12' is a grouser 20. Fig. 2, and this grouser represents the essential tread or ground digging part of the shoe which will enter the ground during the course of movement of the vehicle, thereby introducing forward movement of the vehicle as will be recognized from Fig. 6. The grouser has a fiat upper edge 20F, Fig. 1 which will first dig into the ground, and the grouser extends from one side of the shoe to the other. The two opposite grouser ends 20A and 20B, Fig. 3, are inclined inwardly proceeding in a direction away from the sole plate 12, which contributes to easy entry of the grouser into and disengagement from the ground, and the upper or free corners of the grouser are rounded at 20R for the purpose mentioned above.

As will be observed in Fig. 2, the upper edge of the grouser is relatively narrow, but the grouser is substantially widened and thickened in the lower sections adjacent the sole plate 12. The end or side surfaces of the grouser are triangulated rearwardly toward the rib 15 to afford end webs or gussets disposable in a vertical plane,

substantially perpendicular to the plane of the plate 12,

' but it will-be noted in Fig. 2 the front side or leading I grouser 20 at the front of the vehicle track T just enter:

side 20L of the grouser is angled rearwardly proceeding from the sole plate toward the upper edge of the grouser. Hence, as will be observed in Fig. 6, a

ing the ground will do so in an even unabrupt fashion in contrast to a rather violent and abrupt thrust in those instances where the leading or front face of the grouser -is perpendicularly straight as the rear or .leading- .face is perpendicularly straight. I have foundthat the angle Of-inclination forthe front .face of:the;grousersho'uld be between 45 and 60 and preferably 60 for thexhest effect. -It-will be appreciated that thezgussets or webs described above have their narrow endswterminating-at thenarrow'edge'of the grouser and hence will easily enten and withdraw from the ground.

important feature of.the presentrinvention-resides in vcantilevering the endsof-the soleplate .12. .Thus, referring to Fig. 3, it will be. observedlthatthe medial portion of the sole. platezlZr is; adapted to be. disposedin a substantially flatz-anditrulyhorizontal plane, whereas under such :circurnstances-zthe respective left and right hand .end' sections; 12L and 12R thereof are tipped or bowed upwardly in divergent inclined planes in respective directions proceeding outwardly from the medialsection of'the' sole plate, and this etfectis particularly evident in Fig. 4. Stated in other words, 'the ground engaging .faces of the sections 12L and 12R will lie infpl'anes that are inclined-downwardly proceeding outwardly from the horizontal medial sectionof the sole' plate whenthe shoe is turned-with the grouser downward, .-.andshence as shown in the somewhat diagrammatic section of Fig. 7, the left and right hand endsections of the sole plate will be those-that first engagethe ground. Accordingly, any tendency due to unevenness'of the. ground or unevenness of the vehicle to bend or distort the sole plate will be resisted by the bowed ends of' thesole plate.

Various different methods of articulating'a plurality of shoes on a track have been resorted tom the past, and these various modes of articulation can be resorted to under the'present invention. However, it should'be pointed out that advantageously in accordancew-iththe present invention the leading end of the shoe 1-0,'Fig. 2, is provided with a downwardly bowed front-fiange 30 formed with a pair of spaced mounting sockets 31 which open at the free or leading edge of the front flange 30. The sole plate. 12 at the remote rear portion thereof-is bowed concave upwardly at 35, Fig. 2, in order to engage complementally the upper surface of the frontflange 30 of the'trailing shoe 10 in the articulated assembly.

The shoe assembly is commonly bolted to the track of the vehicle, and it has been found that the bolt openings formed in the sole plates of'the-shoes have tended to become stretched and distorted after prolonged use'due tov the rather severe bending and twisting actions that occur. This distortion and expansion of the bolt openings occurs particularly in the case of manganese steel, which is a relatively ductile "material, andin any even-t it is not long before the shoes must be somehow retightened. In accordance with the present invention, I overcome this particular problem by initially forming the various bolt openings as 36 in the sole plate 12,Fig. 1, of an undersized diameter. compared to the fastening bolts that will be passed through the openings 36 in connecting shoes as 10 to the track. Subsequent to this, and before final assembly, a pin P, Fig.18, having'the diameter of the fastening bolts is then driven through'the undersized openings 36 to enlarge and work-hardenthe same at the areas WH immediately surrounding the bolt openings. Consequently, the final openings 36in a sole plate 12 of manganese steel or like ductile ferrous metalaalloy will be hardened sufliciently to resist'the deformingzaction of the fastening bolts in use.

.Many advantages of the present inventionrhave been the ground engaging face of the plate 12, the cantilevered stressed in connection with: the variousistructural details. 1

It. should be further mentioned T that the downward line end sections of the sole plate and the rounded corners, instead of internal ribbing for additional strength, reduces the tendency of the shoe to be clogged with dirt and other soft material which eventually reduces traction; and the cantilevered ends achieve a great deal of resistance to bending without the added weight of special ribs. In other words, great strength is achieved by the peripheral rib 15 which cooperates with the grouser to define:a;:dish-shaped cavity in the shoe unoccupied *by any othenprojections. Additionally, the work-hardened bolt holes reduce to a minimum repair and replacement due .tothe commony encountered stretching.

Hence, while I have illustrated and described a preferredembodiment of my invention it is to be understood that this is capable of variation and modification, and I therefore do not-wish to be limited to the precise'details setforth, but desire to avail myself of such changes andalterations as fall within the purview of the following claims.

I claim:

1. A ground engaging shoeof the kind described for the track of a track-laying overland vehicle and comprising a sole plate of generally rectangular dimension, said sole plate having a medial section disposable in a horizontalplane and left and right hand side sectionsysaid sole plate having a ground engaging face extended to 'all of said sections, a grouser projecting from the ground engaging face of said'sole plate, a raised'rib formed about the periphery of the ground engaging face of said sole plate rearwardly of said grouser, and the ground engaging faces of'the left and right hand sections of said sole plate lying in respective divergent planes that are inclined upwardly proceeding outwardly of said medial section when disposed in a horizontal plane as aforesaid, therib, the grouser, the medial, and inclined left and right sections of the sole plate presenting an inverted dish-shaped configuration to a supporting medium.

2. -A-shoe according to 'claim 1 wherein the grouser has a forward face that is inclined rearwardly proceeding upwardly from the sole plate, and wherein the sole plate is of substantially uniform cross-section thickness.

3. A-shoe according to claim 2 wherein the upper end corners of the grouser are rounded, and wherein'the rib is rounded to define with the grouser is a dished recess unoccupied by other ribs.

4. A ground engaging shoe of the kind described for the track of a track-laying overland vehicle and comprising, a sole plate composed of manganese steel and being generally of rectangular dimension and of uniform crosssectional thickness, said sole plate being formed with bolt receiving openings which have Work-hardened side walls, said sole plate having a medial section disposable in. a horizontal plane and left and right hand side sections extending outwardly of said medial section at opposite sides thereof, said sole plate having a ground engaging face extended to. all of said sections, a grouser projecting upwardly from the ground engaging face of said soleplate when the medial section is in its horizontal plane, said I grouser having a substantially vertically straight rearface in a plane normal to said horizontal plane and having a front face which isinclined rearwardly proceedingupwardly from the sole plate approximately at an angle of between 45 and 60 when the medial section is in its horizontal plane, the upper end corners of said grouser being'rounded, araised rib of rounded cross sectionextending about the peripheral edge of the ground engaging face of the sole plate rearward of the grouser, and the ground engaging faces of said left and right hand sections of the sole plate lying in respective divergent planes that are inclined upwardly in a direction proceeding outwardly of the opposite sides of said medial section of the sole plate, the portion of the sole plate rearwardly of the grouser presenting an inverted dish-shaped configuration to a supporting medium.

5. A track shoe comprising, a sole plate of generally rectangular configuration and having a bearing surface, a grouser projecting from the bearing surface of the sole plate and extending across the sole plate so as to divide the bearing surface of the sole plate into first and second portions, the first portion of the bearing surface of the sole plate having a generally flat horizontal central section and fiat inclined side sections, the inclination of the side sections being such that the outermost edges of the side sections are projected from the plane of the central section in the same direction as the projection of the grouser, a rounded rib projecting from the periphery of the first portion of the bearing surface of the sole plate and joined to the grouser in smoothly formed gussets, the grouser, rounded rib, gussets and central and side sections of the first portion of the bearing surface of the track shoe presenting an inverted dish-shaped configuration to a supporting medium.

References Cited in the file of this patent UNITED STATES PATENTS 

